Medical laser apparatus and diagnostic/treatment apparatus using the medical laser apparatus

ABSTRACT

In photodynamic diagnosis and photodynamic therapy, the oscillating wavelength of laser light from a light source is fitted to a plurality of different kinds of photosensitizers and exciting conditions thereof. Moreover, diagnosis and treatment are achieved using concurrent diagnosis during treatment is realized as well. A semiconductor laser generates laser light having an oscillating wavelength which is variable and a full width at half maximum which is narrow. A light transmission line guides an irradiated laser light to the vicinity of a focus, an image transmission line observes the focus and the periphery thereof, a fluorescence light extracting device extracts only the fluorescence light emitted from a photosensitizer excited by the irradiated laser light, an image-pick-up/analyzing device picks up and analyzes an image of the extracted fluorescence light and an image display device displays the analyzing result.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This is a divisional application of Ser. No. 09/406,734, filedSep. 28, 1999 which is a divisional application of Ser. No. 08/545,101,filed Oct. 19, 1995 (now U.S. Pat. No. 6,214,033) which is acontinuation-in-part of Ser. No.08/174,370, filed Dec. 28, 1993, nowabandoned.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a medical laser apparatus to beused as a light source for a diagnostic/treatment apparatus which treatsa focus of a tumor such as a cancer or the like through irradiation oflight to the focus. When light having a wavelength coinciding with theabsorption wavelength of a photosensitizer which has an affinity to thefocus and has been preliminarily accumulated in the focus is irradiatedto the focus, the photosensitizer is excited, making it possible todiagnose or treat the focus. The present invention relates alike to adiagnostic/treatment apparatus using the medical laser apparatus.

[0003] In accordance with the development of electronic medical-caretechnology, photodynamic diagnosis (referred to as PDD hereinbelow) andthe photodynamic therapy (referred to as PDT hereinafter), eachutilizing laser light, have made rapid progress recently. In PDD andPDT, a photosensitizer having affinity to a tumor and capable of aphotochemical reaction, e.g., an emission of fluorescence or a cellcidalaction is accumulated in a focus of the tumor beforehand, and then lightis irradiated to the focus, which induces the excitation of thephotosensitizer, to thereby permit diagnosis of the focus by measuringthe emitted fluorescence (PDD) or treatment of the focus by thecellcidal action (PDT). It is preferable that the wavelength of thelight irradiated to the focus coincides with the absorption wavelengthof the photosensitizer in order to efficiently excite thephotosensitizer, and therefore a laser light source has been generallyemployed as a light source of the light irradiating to the focus. Inthis case, the laser light source is fitted to the absorption wavelengthof the photosensitizer being used.

[0004] A dye laser which uses hematoporphyrin as a photosensitizer andan excimer laser as a laser light source (referred to as an excimer dyelaser hereinbelow) has been often used in the above-described type ofdiagnostic/treatment apparatus for diagnosing and treating cancers, asis discussed in Japanese Patent Publication Nos. 63-2633 (2633/1988) and63-9464 (9464/1988). The conventional diagnostic/treatment apparatususing the laser device disclosed in the noted publications will bedescribed with reference to FIG. 4.

[0005]FIG. 4 schematically shows the constitution of a cancerdiagnostic/treatment apparatus using a conventional laser apparatus. InFIG. 4, A is a focus of a cancer and B indicates the peripheral pair ofthe focus A where hematoporphyrin has been absorbed as a photosensitizerbeforehand. A first pulse source 31 for diagnostic purposes and a secondpulse source 32 for treatment purposes are both constituted of anexcimer dye laser. An excimer dye laser for exciting the first andsecond dye lasers 31, 32 repeatedly oscillates with an oscillatingwavelength 308 nm and pulse width 30 ns while varying the energy in therange of several mJ-100 mJ. The oscillating wavelength of the firstpulse source 31 is 405 nm and that of the second pulse source 32 is 630nm. The first and second pulse sources 31, 32 are switched by aswitching part 33. The other reference numerals represent: 34 a lighttransmission line; 35 a TV camera; 36 a TV monitor; 37 a half mirror; 38a spectroscope; 39 a spectrum analyzing part; and 40 a display unit.

[0006] The diagnosing/curing apparatus of the above-describedconstitution operates as follows

[0007] When a cancer is to be diagnosed, a laser light of the wavelength405 nm generated from the first pulse light source 31 is irradiated tothe focus A and the peripheral part B through the switching part 33 andthe light transmission line 34. A fluorescence image of the wavelength630 nm, 690 nm excited by the laser light of 405 nm wavelength isphotographed by the TV camera 35 and displayed for observation on thescreen of the TV monitor 36. At the same time, the fluorescence image isextracted by the half mirror 37 and divided by the spectroscope 38. Thespectrum is analyzed in the spectrum analyzing part 39 and thewavelength of the spectrum is displayed by the display unit 40. In orderto treat the cancer, then, a laser light of the wavelength 630 nmproduced by the second pulse light source 32 is, through the switchingpart 33 and the light transmission line 34, irradiated to the focus A.The operation mode is subsequently switched to the diagnosing mode againto thereby confirm the result of the treatment. The cancer is diagnosedand treated by repeatedly switching the modes as above.

[0008] In addition to the fact that the fluorescence peculiar tohematoporphyrin is efficiently excited by the light of the wavelength405 nm, adverse influences resulting from scattering light can also berestricted due to the difference of the wavelengths 630 nm and 690 nm ofthe fluorescence, the first pulse light source 31 for diagnosticpurposes thus uses the wavelength 405 nm. Meanwhile, the second pulselight source 32 for treatment purposes is set at the wavelength 630 nmbecause the laser light of the wavelength 630 nm transmits well throughthe tissue and is efficiently absorbed in hematoporphyrin.

[0009] In addition to the aforementioned example, the photosensitizersin (Table 1) below are proposed for use in PDD and PDT and also thelasers shown in (Table 1) are tried to be used as a laser light sourcefor PDT. TABLE 1 Laser light source Absorption (projection wave-Disadvantages of Photosensitizer wavelength length [nm]) laser devicesHpD 630 Excimer dye laser *Deterioration of Argon dye laser solution ofcoloring (624 ± 6.5 nm) matter is fast *Bulky and expensive HpD 630 GoldVapor laser *Necessary to warm (627.8 nm) up for 30 mm. or more *Life ofgas and oscillating tube is short *Bulky and expensive PH-1126 650Krypton laser *Life of gas is short (647 nm) *Bulky and expensive NPe6664 Argon dye laser *Deterioration of (667 ± 5 nm) solution of coloringmatter is fast *Bulky and expensive

[0010] A drawback of the conventional diagnostic/treatment apparatus ofcancers resides in the fact that the wavelength of the projected laserlight is difficult to control.

[0011] In other words, it is necessary to make the wavelength of thelaser light coincident with the absorption band of the photosensitizerso as to efficiently excite the photosensitizer. Generally, it is notpossible for the gas laser (Table 1) to meet the absorption band of aplurality of the photosensitizers. Moreover, it is difficult for the gaslaser to have a wavelength which coincides with the maximum absorptionwavelength of even a single photosensitizer. Although a dye laser asdepicted with reference to the above conventional example has beenemployed to solve the problem, it is necessary to exchange the solutionof a coloring matter in order to change the oscillating wavelength ofthe dye laser. Therefore, a plurality of dye lasers corresponding to aplurality of different kinds of solutions of a coloring matter should beprepared and exchanged for every wavelength if the wavelength of thelaser light is required to be changed, for instance, when thephotosensitizer being used is changed or when the wavelength of thelaser light is changed during treatment relative to that used duringdiagnoses.

[0012] In the case where the dye laser is used, therefore, thediagnostic/treatment apparatus becomes disadvantageously bulky in sizeto accommodate a plurality of different kinds of coloring mattersolutions and a switching of the solutions.

[0013] A second disadvantage of the diagnostic/treatment apparatus usingthe dye laser is that the solution of a coloring matter of the dye lasereasily deteriorates, inviting a change of the wavelength of theresultant laser light or a decrease of the output. Since the safety ofthe laser light is an essential and indispensable condition to ensurethe effect of PDD and especially PDT, a substantial problem of the dyelaser arises when the solution of the coloring matter should beexchanged or a circulator of the coloring matter should be cleanedfrequently. Further, the wavelength of the laser light is undesirablychanged or the laser output is decreased during the irradiation if thesolution used in the dye laser easily degrades, that is, the irradiatingcondition of the laser light should be set with such changes in thewavelength or output as above taken into consideration and, the changeof the laser light should be arranged to be detected.

[0014] Thirdly, when the wavelength is converted by the dye laser, thefull width at half maximum (FWHM) of the wavelength of the obtainedlaser light expands to at least 10 nm or so. If the full width at halfmaximum is wide, the laser light increasingly shifts from the absorptionband of the photosensitizer, thus worsening the exciting efficiency ofthe photosensitizer. Although it may be arranged to reduce the fullwidth at half maximum of the dye laser by using a band pass filter or adiffraction grating, only the excessive component is cut, but theexciting efficiency is left unimproved.

[0015] A fourth drawback is the poor converting efficiency of energy ofthe dye laser when the wavelength is converted. Therefore, the excimerlaser, etc. used as a light source to excite the dye laser is requiredto generate a high output in order to achieve sufficient energy from theconverted laser light. In other words, the conventional medical laserapparatus and the diagnostic/treatment apparatus of cancers using theconventional medical laser apparatus are liable to be bulky andexpensive.

[0016] A fifth drawback inherent in the prior art resides in the needfor two light sources for diagnostic purposes and for treatment purposeas well as the switching mechanism to switch the light sources. Theapparatus consequently is bulky and expensive and moreover, it isinconvenient to switch the light sources and erroneous manipulation canoccur.

SUMMARY OF THE INVENTION

[0017] The object of the present invention is therefore to provide, witheliminating the aforementioned drawbacks of the conventionalapparatuses, a compact and inexpensive medical laser apparatus whichachieves laser light of the oscillating wavelength fit for a pluralityof kinds of photosensitizers and also a plurality of exciting conditionsthereof, and is maintenance-easy with a narrow fall width at halfmaximum and good exciting efficiency.

[0018] A further object of the present invention is to provide adiagnostic/treatment apparatus using the medical laser apparatus whichrealizes both diagnosis and treatment by a single light source tothereby make a diagnosis simultaneously during the treatment.

[0019] In accomplishing these and other objects, according to a firstaspect of the present invention, there is provided a medical laserapparatus designed to diagnose or treat a focus by irradiating lightfrom a light source to the focus where a photosensitizer having anaffinity to the focus has been preliminarily accumulated to therebyexcite the photosensitizer, the apparatus comprising: a laser as thelight source which is capable of controlling oscillating wavelength andwhich has a full width at half maximum which is narrower than a width ofa band, where an energy absorption of the photosensitizer is equal to ormore than 90% of the maximal value in the vicinity of the oscillatingwavelength; and a wavelength controlling means for controlling thelaser.

[0020] According to a second aspect of the present invention, there isprovided a diagnostic/treatment apparatus designed to diagnose or cure afocus by irradiating light from a light source to the focus where aphotosensitizer having an affinity to the focus has been preliminarilyaccumulated to thereby excite the photosensitizer, thediagnostic/treatment apparatus comprising: a medical laser apparatuswhich comprises a laser as the light source which is capable ofcontrolling oscillating wavelength and which has a full width at halfmaximum which is narrower than a width of a band, where an energyabsorption of the photosensitizer is equal to or more than 90% of themaximal value in the vicinity of the oscillating wavelength, and awavelength controlling means for controlling the laser; a lighttransmission line for guiding the laser light projected from the medicallaser apparatus to the vicinity of the focus; an image transmission linefor guiding fluorescence emitted from the photosensitizer excited by thelaser light to observe the focus and a periphery thereof; a fluorescenceseparating means for separating only the fluorescence; and animage-picking-up/analyzing means for picking up and analyzing an imageof the fluorescence obtained by the fluorescence separating means.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] These and other objects and features of the present inventionwill become clear from the following description taken in conjunctionwith the preferred embodiments thereof with reference to theaccompanying drawings, in which:

[0022]FIG. 1 is a block diagram showing the constitution of a medicallaser apparatus according to a first embodiment of the presentinvention;

[0023]FIG. 2 is a block diagram showing the constitution of adiagnostic/treatment apparatus according to a second embodiment of thepresent invention;

[0024]FIG. 3 is a characteristic diagram of a band pass filter used inthe second embodiment of the present invention; and

[0025]FIG. 4 is a block diagram showing the constitution of adiagnostic/treatment apparatus of cancers using a conventional laserapparatus.

[0026]FIG. 5 is a block diagram of a apparatus according to a thirddiagnostic/treatment apparatus according to a third embodiment of thepresent invention;

[0027]FIG. 6 is a detailed block diagram of control means of thediagnostic/treatment apparatus of the third embodiment of the presentinvention; and

[0028]FIG. 7 is a graph showing a relationship between wavelength andexcitation efficiency of an exemplified photosensitizer;

[0029]FIG. 8 is a schematic flowchart showing a procedure of treatmentand/or diagnosis by means of the diagnostic/treatment apparatus of thethird embodiment of the present invention;

[0030]FIG. 9 is a flowchart showing a diagnosing step of FIG. 8;

[0031]FIG. 10 is a f flowchart showing a laser apparatus setting step ofFIG. 8;

[0032]FIG. 11 is a flowchart showing a wavelength setting step of theFIG. 10;

[0033]FIG. 12 is a flowchart showing a probe mounting step of FIG. 10;

[0034]FIG. 13 is a flowchart showing an output and energy setting stepof FIG. 10; and

[0035]FIG. 14 is a flowchart showing control of irradiation energyquantity of FIG. B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Before the description of the present invention proceeds, it isto be noted that like parts are designated by like reference numeralsthroughout the accompanying drawings.

[0037] [First Embodiment]

[0038] A medical laser apparatus according to a first embodiment of thepresent invention will be discussed hereinbelow with reference to theaccompanying drawings.

[0039] The constitution of a medical laser apparatus according to afirst embodiment of the present invention is shown in FIG. 1. Referringto FIG. 1, an AlGaInP semiconductor laser 1 has an oscillating frequency664 nm, full width at half maximum (FWHM) of ±1 nm, temperaturecharacteristic of the oscillating wavelength 0.2 nm/deg, and operabletemperature range −100 through +80° C. during driving at 0° C. Anoptical system 2 separates a laser light 3 projected from thesemiconductor laser 1 to an irradiating laser light 3 a and a wavelengthdetecting laser light 3 b. A photosensitizer 6 is preliminarilyadministered in a target portion to be treated 5 including a focus A anda peripheral part B of the focus A. The other reference numeralsindicate: 4 an optical fiber; 7 a control unit; 8 a temperaturecontrolling device; 9 a wavelength detecting unit for detecting thewavelength of the laser light 3 b; 10 a wavelength displaying unit; and11 a shutter working as an automatic irradiation stopping unit inassociation with the control unit 7.

[0040] The operation of the medical laser apparatus having theconstitution as above will be described below.

[0041] The wavelength of the laser light 3 projected from thesemiconductor laser 1 is determined by the temperature of thesemiconductor laser 1. That is, when the temperature of thesemiconductor laser 1 is varied in the range of −100 through +80° C. bythe temperature controlling device 8, the wavelength of the laser light3 is changed within 644 through 680 mn. Accordingly, the wavelength ofthe laser light 3 is obtained which is suited to the absorptionwavelength of the using photosensitizer 6 and the purpose of thetreatment.

[0042] In the instant embodiment, NPe6 (trade name of NipponPetrochemical Co., Ltd.) of a chlorin group in (Table 1) is used as thephotosensitizer 6. The temperature of the semiconductor laser 1 is setat 0° C. when the laser light 3 of the center wavelength 664 mn in theabsorption band of 660 nm through 668 nm of the photosensitizer 6 isdesired. On the other hand, the temperature of the semiconductor laser 1is controlled to be −15° C. in order to obtain the laser light of theshorter wavelength 660 nm in the absorption band for a purposed to bedescribed later. When the laser light 3 of the center wavelength 650 nmand the shorter wavelength 644 nm in the absorption band of 647 nmthrough 653 nm is to be obtained with the use of PH-1126 (trade name ofHamari Chemicals, Ltd.) of a pheophorbide group (Table 1), thesemiconductor laser is controlled to be −70° C.-100° C., respectively.The full width at half maximum is narrower than a width of theabsorption band, where an energy absorption of the photosensitizer isequal to or more than 90% of the maximal value in the vicinity of theoscillating wavelength.

[0043] Since the full width at half maximum is ±1 nm, the wavelength ofthe laser light 3 projected from the semiconductor laser 1 controlled atthe temperature 0° C., −15° C.-70° C., and −100° C. is 663-665 nm,659-661 nm, 649-651 nm, and 643-645 nm, that is, the energy of the laserlight 3 is held within the absorption band of the photosensitizer 6being used.

[0044] A part of the laser light 3 from the controlled semiconductorlaser 1 is separated by the optical system 2 and guided to thewavelength detecting unit 9 as the wavelength detecting laser light 3 b.The detecting unit 9 detects the wavelength of the laser light 3 b. Thedetected result is sent to the control unit 7. It is decided by thecontrol unit 7 whether the laser light 3 b matches a predeterminedcondition to control the wavelength thereof. The detecting result andthe value of the wavelength is displayed by the wavelength displayingunit 10. The control unit 7 activates the automatic irradiation stoppingunit 11 in case the laser light 3 b does not match the predeterminedcontrolling condition so as to shut the irradiating laser light 3 a.

[0045] When the laser light 3 conforms to the predetermined controllingcondition, the shutter 11 is opened and the irradiating laser light 3 ais condensed into the optical fiber 4 to be irradiated to the targetportion 5 from an end of the optical fiber 4.

[0046] As described hereinabove, the oscillating wavelength of the laseris controlled to thereby obtain the laser light of the wavelength of thenarrow full width at half maximum which is suited to the absorptionwavelength of a plurality of kinds of photosensitizers and the purposeof the treatment, so that the photosensitizers can be excitedefficiently. Moreover, the laser apparatus is almost maintenance-free,compact in size and inexpensive.

[0047] [Second Embodiment]

[0048] A diagnostic/treatment apparatus of cancers according to a secondembodiment ofthe present invention will be discussed with reference toFIGS. 2 and 3.

[0049]FIG. 2 is a block diagram showing the constitution of thediagnostic/treatment apparatus of cancers according to the secondembodiment of the present invention. In FIG. 2, reference numeral 21denotes a laser light source which is the medical laser apparatus usingthe semiconductor laser disclosed in the foregoing first embodiment, 22denotes a light transmission line through which the irradiating laserlight 3 a from the laser light source 21 is introduced to the vicinityof the focus, and 23 denotes an image transmission line through which animage of fluorescence is transmitted to observe the focus and theperiphery of the focus. A light guiding device 24 incorporating thelight transmission line 22 and the image transmission line 23 guidesboth the lines 22 and 23 to the vicinity ofthe focus. Animage-picking-up/analyzing unit 25 picks up images in the vicinity ofthe focus through the image transmission line 23 and analyzes theimages. The analyzing result is displayed by an image displaying unit26. A band-pass filter 27 with a considerably narrow band width, i.e.,approximately ±3 nm to the designated wavelength is composed of adielectric multi-layer film (for example, a total dielectricinterference filter DIF of Vacuum Optics Corporation of Japan having thecharacteristic shown in FIG. 3). The band-pass filter 27 allows only thelight of the wavelength in the vicinity of that of fluorescence ofthephotosensitizer being used separately from the irradiating laser light 3a to pass. The passing wavelength is approximately 670 nm when thephotosensitizer of a chlorin group is used, or approximately 654 nm whenthe photosensitizer of a pheophorbide group is used. The band-passfilter 27 is placed on an optical axis connecting the image transmissionline 23 with the image-picking-up/analyzing unit 25. It is to be notedhere that the band-pass filter 27 can be equipped with a plurality ofband-pass filters respectively corresponding to a plurality ofphotosensitizers, and also a switching means (not shown) to switch theband-pass filters. The remaining reference numerals, for instance, 5 andthe like represent the same parts as in FIG. 1.

[0050] The operation of the diagnostic/treatment apparatus of cancersconstituted in the above-described arrangement will be depicted below.

[0051] In the first place, the irradiating laser light 3 a projectedfrom the laser light source 21 is irradiated via the light transmissionline 22 to the target portion 5 where the photosensitizer has beenpreliminarily accumulated. At this time, the laser light 3 a iscontrolled by the temperature controlling device to attain the centerwavelength of the absorption band of the photosensitizer so that thetreatment results in the optimum effect. In other words, the wavelengthof the laser light 3 a is controlled to be 664 nm and 650 mn when NPe6and PH-1126 are used as the photosensitizer, respectively. Thecontrolling operation has been described earlier in the firstembodiment.

[0052] When the laser light 3 a is irradiated to the target portion 5,the focus A is selectively treated by the action of the photosensitizeraccumulated there beforehand. At the same time, the photosensitizer inthe focus A is excited by the laser light 3 a and consequently emitsfluorescence of the specified wavelength as described before. The targetportion 5 is thus diagnosed by analyzing the image of fluorescence. Thefluorescence shows the wavelength considerably approximate to that ofthe irradiating laser light 3 a and has the weak intensity, andtherefore is strongly influenced by the scattering light of the laserlight 3 a. It is hence conventionally generally difficult to pick up andanalyze the image of fluorescence.

[0053] As such, the fluorescence is guided through the band-pass filter27 via the image transmission line 23 according to the instantembodiment. More specifically, the fluorescence is passed through theband-pass filter 27 which has such characteristic as exemplified in FIG.3 and allows only the fluorescence emitted from the photosensitizerbeing used to pass while shutting the irradiating laser light 3 a,whereby the influences of the scattering light of the laser light 3 aare eliminated. As a result, the image of fluorescence alone is inputtedto the image-picking-up/analyzing unit 25. Theimage-picking-up/analyzing unit 25 picks up and analyzes the image dataof fluorescence, the result of which is displayed at the imagedisplaying unit 26 such as a television and recorded in a recording unitsuch as a VTR. By observing the display, the focus A can be diagnosed inreal time even in the middle of the treatment.

[0054] It is also possible to control and shift the wavelength of theirradiating laser light 3 a from that of the fluorescence with an aim toimprove the separation of the fluorescence (S) from the scattering light(N) of the irradiating laser light 3 a (S/N ratio). That is, theirradiating laser light 3 a may be controlled to be shifted from thecenter wavelength in the absorption band of the photosensitizer beingused (e.g., 664 nm or 650 nm when NPe6 or PH-1126 is used) to be awayfrom the wavelength of the fluorescence within the absorption band(e.g., 660 nm or 644 nm when NPe6 or PH-1126 is used). If the wavelengthofthe irradiating laser light 3 a is controlled as above, the S/N ratiois improved. At the same time, since the energy of the irradiating laserlight 3 a is kept within the absorption band of the photosensitizer asdescribed earlier in the first embodiment, the treatment effect ishardly deteriorated.

[0055] The oscillating wavelength of the laser light 3 can be madevariable also in a diagnostic/treatment apparatus which uses only aspecific photosensitizer (for instance, NPe6 or PH-1126) within therange of the effective absorption band of the photosensitizer (e.g.,664±5 nm or 650±10 nm in the case of NPe6 or PH-1126).

[0056] Since the wavelength of the irradiating laser light 3 a can becontrolled easily in the medical laser apparatus of the embodiments ofthe present invention, even when the concurrent diagnosis with thetreatment becomes unnecessary, it is possible to return the wavelengthof the irradiating laser light 3 a to the center wavelength of theabsorption band of the photosensitizer, that is, the optimum wavelengthfor the treatment. Moreover, it is an advantage of the medical laserapparatus of the embodiments to display whether the wavelength of thelaser light 3 conforms to the controlling condition. If the wavelengthof the laser light 3 is not in compliance with the controllingcondition, the laser light is shut off as mentioned before.

[0057] Accordingly, due to the band-pass filter provided in thediagnostic/treatment apparatus of the embodiments, it becomes possibleto execute diagnosis and treatment concurrently using a single laserlight source. The wavelength ofthe laser light is controlled by thewavelength controlling unit to be away from the wavelength of thefluorescence emitted by the photosensitizer within the absorption bandof the photosensitizer, so that the S/N ratio ensuring stable imagesduring the concurrent diagnosis with the treatment is satisfied.

[0058] Although the laser in the first embodiment is a semiconductorlaser, the other kinds of lasers can be employed so long as the fullwidth at half maximum is narrow and the oscillating wavelength of thelaser light is variable. Needless to say, the semiconductor laser 1 isnot limited to the one having the characteristic described in the firstembodiment. For example, the laser can be made up of an externalresonating type semiconductor laser in which the wavelength iscontrolled by an external change of the resonance. Further, although thetemperature is controlled in the arrangement of feedback control bymeans ofthe wavelength detecting unit 9 in the first embodiment, it ispossible to control the wavelength correctly if a memory means storingthe relationship between the temperature and the oscillating wavelengthof the semiconductor laser is provided to control the temperature of thesemiconductor laser based on the relationship.

[0059] As is fully described hereinabove, the medical laser apparatus isprovided with the laser as a light source and the wavelength controllingunit for the laser. This laser emits the laser light of the narrow fullwidth at half maximum and the oscillating wavelength of the laser lightis variable. Therefore, the medical laser apparatus is able to achievethe oscillating wavelength suitable for the kind of the photosensitizerbeing used as well as the exciting condition of the photosensitizer, andthus efficiently excite the photosensitizer. Moreover, the medical laserapparatus is advantageously almost maintenance-free, compact andinexpensive.

[0060] According to the diagnostic/treatment apparatus of the presentinvention, since the image of fluorescence is displayed by the imagedisplaying unit also during the treatment ofthe focus, it becomespossible to diagnose and treat the focus using a single light source,and to make diagnosis of the focus during the treatment in the simpleand compact structure. The diagnostic/treatment apparatus is easy tohandle.

[0061] A third embodiment of the present invention will be discussedbelow.

[0062] The third embodiment is effective in solving the followinginconveniences. When neither permeability of irradiating light to afocus when the irradiating light reaches the focus nor irradiationenergy of irradiating light relevant to a treatment effect throughexcitation efficiency characteristics of a photosensitizer iscontrolled, and when a wavelength of a laser light shifts from anoptimum absorption wavelength ofthe photosensitizer, there is adisadvantage that photochemical reaction quantity of the irradiatinglight having an equal output intensity is reduced due to the degradationof an excitation effect ofthe photosensitizer. Furthermore, when aspecifically set output cannot be obtained due to an abnormality of thelaser, a protection means built in the laser apparatus operates to causea disadvantage in that the treatment cannot be effected. There is afurther disadvantage in that irradiating light having an equal outputcannot be obtained with respect to an emission laser light having anequal output (in output intensity and intensity distribution) due to thetype of a laser probe to be used in connection with a main unit of thediagnostic/ treatment apparatus, a variation and deterioration with anelapse of time of transfer characteristics of each probe and so forth.

[0063] In order to solve the above-mentioned disadvantages, thediagnostic/treatment apparatus of the third embodiment comprises:irradiation energy quantity control means for controlling theirradiation energy quantity of irradiating light; control means forcontrolling the laser so that the irradiation energy quantity of theirradiating light becomes a specified quantity; irradiating lightcharacteristic measuring means for measuring irradiation characteristicsof the irradiating light irradiated from an optical transmission pathfor transmitting light from a light source to a focus; a plurality oflaser units which serve as the light source; oscillation control meansfor controlling the total oscillation characteristics by individuallycontrolling the plurality of laser units; and wavelength correctionmeans for correcting a control target value of the irradiation energyquantity by the wavelength of the irradiating light.

[0064] Practically, as shown in FIG. 5, there are provided twosemiconductor laser units 51 a and 51 b each of which is provided with asemiconductor laser 1 shown in FIG. 1, the temperature controllingdevice 8 for controlling the wavelength of emission light by controllingthe temperature of the semiconductor laser 1, and a wavelength detectingunit 9 for detecting the output characteristics of wavelength, outputintensity, oscillation efficiency and so forth ofthe emission light.Emission beams of laser light 72 a and 72 b, emitted respectively fromthe units 51 a and 51 b, are guided to an emission outlet 75 viashutters 11 a and 11 b, a half mirror 74 a, and a total reflectionmirror 74 b. There is provided the control unit 7, and as shown in FIG.6, it is comprised of: a setting condition storage section 85; awavelength correcting section 56; an oscillation control section 57; atime measuring section 58; an energy quantity control section 59; anemission control section 60; a display control section 61; and anabnormality detecting means 62. The oscillation control section 57 has afunction of individually controlling the semiconductor laser units 51 aand 51 b, and is comprised of an oscillation and stop control section, awavelength control section, an output section, and an irradiating lightintensity control section, and an irradiating light converting section(all of these sections are not shown). It is to be noted that neitherdescription nor illustration is provided for normal functional sectionsof control means, a CPU and the like which are typically associated withan ordinary diagnostic/treatment apparatus. Further shown is an inputsection 52 for inputting a variety of operation conditions, thewavelength displaying unit 10, and an irradiating light characteristicmeasuring means 53 which is comprised of an irradiation outlet forconnecting a foremost end portion 83 of the laser probe 80 and ameasuring section (these sections are not shown). The laser probe 80 iscomprised of a connector 54, to be connected to the emission outlet 75,an optical fiber 82, and the foremost end portion 83. A part A is afocus, and a photosensitizer 6 is preliminarily administered in aportion to be treated 5 including the focus A and a peripheral portion Bofthe focus A. A reference numeral 85 denotes irradiating light to beirradiated from the foremost end portion 83 to the portion to be treated5.

[0065]FIG. 8 is a schematic flowchart showing a procedure of treatmentand/or diagnosis by means of the diagnostic/treatment apparatus of thethird embodiment of the present invention.

[0066] Setting of the laser apparatus is performed in step S1, laserlight irradiation is started in step S2, and selection between treatmentand diagnosis is performed in step S3. When treatment is selected instep S3, the program flow proceeds to step S4 to control an irradiationenergy quantity in step S4. Then, it is decided whether or not theirradiation is completed in step S5. When the irradiation is notcompleted, the operations of step S4 and step S5 are repeated. When theirradiation is completed in step S5, the program flow terminates as theresult of correct achievement of the treatment (which is indicated inFIG. 8 as “normal end”). Otherwise, when diagnosis is selected. in stepS3, the program flow proceeds to step S6 to perform diagnosis and thenproceeds to step S7 to control an irradiation energy quantity in stepS7, and it is decided whether or not the irradiation is completed instep S8. When the irradiation is not completed, the operations of stepS6 through step S8 are repeated. When the irradiation is completed instep S8, the program flow terminates as the result of the correctachievement of the treatment.

[0067]FIG. 9 is a flowchart showing the diagnosing operation in step S6of FIG. 8. According to this flowchart, an image of fluorescence isextracted by a bandpass filter (fluorescence light separating means) 27in step S61. Then, the image of fluorescence is analyzed in step S62.Then, the analyzed image of fluorescence is displayed in the displayingunit 10 in step S63.

[0068]FIG. 10 is a flowchart showing the laser apparatus settingoperation in step S1 of FIG. 8. According to this flowchart, setting ofwavelength is performed in step S11, setting of the probe is performedin step S12, and setting of output and energy quantity is performed instep S13.

[0069]FIG. 11 is a flowchart showing the wavelength setting operation instep S11 of the FIG. 10. According to this flowchart, a main switch ofthe entire apparatus is turned on in step S11, and wavelength control isstarted in step S112. In this case, the laser wavelength is set to adefault wavelength which is a target value. In the present embodiment,the wavelength of the laser light of the semiconductor laser iscontrolled by temperature. For example, in the present embodiment, thesemiconductor laser is cooled down to a temperature of 0° C. in order toobtain a wavelength of 664 nm in conformity to an absorption wavelengthcharacteristic ofa photosensitizer NPe6 to be used as one example. The“wavelength control start” as described above means start of atemperature control targeted at the temperature of 0° C. In this case,the default wavelength is 664 nm. The default wavelength may be fixed inthe shipping stage of the apparatus, or the previously used conditionmay be used as the default value.

[0070] The above-mentioned operation is an operation concerningtemperature control of the semiconductor laser, and therefore theoperation is achieved by controlling the temperature controlling device8 included in each of laser units 51 a and 51 b by the oscillationcontrol section 57 based on the default wavelength stored in the settingcondition storage section 55.

[0071] Subsequently, setting of a fundamental wavelength is performed instep S113. In this case, selection of a medicine name or numerical valuesetting is performed. The fundamental wavelength is the optimumabsorption wavelength of a photosensitizer to be used for treatment, andthe fundamental wavelength of, for example, NPe6 of the presentembodiment is 664 nm. The wavelength depends on the photosensitizer tobe used, and therefore, when the photosensitizer is changed, thewavelength ofthe laser light is required to be changed according to thephotosensitizer. That is, when the photosensitizer is decided, thefundamental wavelength thereof is decided. Therefore, in setting thewavelength of the apparatus, the wavelength can be selected by the nameof the photosensitizer to be used other than direct input of theintended wavelength. For example, names of plural photosensitizers maybe displayed in the displaying unit 10 of the apparatus. When NPe6 isselected from names at the input section 52, the fundamental wavelengthis set to 664 nm. When PH-1126 is selected, the wavelength is set to 650nm. Further, the fundamental wavelength can be directly set (numericallyset) at the input section 52 so that even a photosensitizer having aname is not listed in the names of the photosensitizers preparatorilystored in the apparatus, such as a photosensitizer newly developed, canbe used.

[0072] Subsequently, in step S114, selection between treatment anddiagnosis is performed. When diagnosis is selected, the program flowproceeds to step S115. When treatment is selected, the program flowproceeds to step S116. In step S115, fine tuning of the wavelength isperformed. If required, excitation efficiency is set. When diagnosis isperformed concurrently with treatment as described in the secondembodiment, an image of fluorescence is obtained from an observed imageby the band-pass filter (fluorescence light separating means) 27 whichinterrupts the irradiating laser light and transmits only fluorescencelight. In the above stage, in order to improve a signal-to-noise ratioS/N of the fluorescence light to be transmitted (S) to the irradiatinglaser light to be cut off (N), a wavelength control for putting thewavelength of the irradiating laser light away from the wavelength ofthe fluorescence light is performed. For example, when thephotosensitizer to be used is NPe6 in the second embodiment, the optimumwavelength (fundamental wavelength) is 664 nm only if treatment is to beperformed. However, when diagnosis is to be performed concurrently withtreatment, the wavelength of the laser light is shifted to 660 nm atwhich the excitation efficiency of the photosensitizer is not reducedtoo much (assuming that the excitation efficiency at the wavelength of664 nm, i.e., the optimum wavelength is 1, the excitation efficiency is0.9 at the wavelength of 660 nm). When diagnosis is performed in amanner as described above, the wavelength of the laser light issometimes intentionally shifted away from the fundamental wavelengthoptimum for treatment, and this is referred to as “fine tuning ofwavelength”. Therefore, according to this operation, in the case wherethe fine tuning of wavelength is effected in order to improve thesignal-to-noise ratio S/N in fluorescence light separation when thesetting of “performing diagnosis” is inputted from the input section 52,the input section 52 is set with the degree at which the wavelength isshifted from the fundamental wavelength. The result is transmitted tothe controlling device 8 in each laser unit 51 a, 51 b via the settingcondition storage section 55, wavelength correcting section 56, andoscillation control section 57, so that the wavelength is changed.

[0073] Subsequently, in step S116, it is decided whether or not thewavelength of the irradiated laser light coincides with the setwavelength. The set wavelength has a range of tolerance. For example,when the photosensitizer to be used is NPe6, it has an absorptionwavelength band of 664±4 nm. Therefore, within this range, there is nosubstantial problem. (Therefore, if the wavelength is set to 660 nm inthe fine tuning of wavelength in the case of diagnosis, the diagnosiscan be achieved while performing treatment.) It is to be noted that, asdescribed in connection with the first embodiment, the wavelength of thesemiconductor laser has a temperature characteristic of 0.2 nm/deg, andtherefore a wavelength accuracy of ±1 nm (corresponding to a temperaturerange of ±5° C.) can be sufficiently achieved in regard to the accuracyof temperature control. The current experimental apparatus has itstolerance of ±1 nm.

[0074] When the laser wavelength coincides with the set wavelength instep S116, the program flow terminates. Otherwise, when they do notcoincide with each other, the program flow proceeds to step S117 todecide whether or not the wavelength control is performed within alimited time. The “limited time” is a limited time from a time when awavelength ofthe irradiating laser light is set to a time when thewavelength is actually obtained. When the wavelength control is notcompleted within the limited time (temperature control in theembodiment), the control unit 7 decides that the temperature controllingdevice 8 (temperature control) of the laser unit 51 a, 51 b is failing,and then stops use of the laser unit.

[0075] It is to be noted that the wavelength control starts with the“turning-on of the power” of the entire apparatus toward the target ofthe default wavelength. Therefore, when no wavelength setting isperformed after the power is turned on, the time point at which thepower is turned on is the start point of the limited time.

[0076] The limited time depends on the capability of a temperaturecontrolling device 8 of each laser unit. In one example, the limitedtime is set at five minutes. However, the time required for the coolingoperation varies significantly depending on the output and the setwavelength of the laser.

[0077] The above-mentioned operation is controlled in the time measuringsection 58, and when an abnormality (error) occurs, the occurrence ofthe abnormality is displayed for alarm in the displaying unit 10 via theoscillation control section 57, abnormality detecting means 62, anddisplay control section 61.

[0078] When the wavelength control is not performed within the limitedtime in step S117, the program flow terminates in step S118 as theresult of the occurrence of the abnormality. When the wavelength controlis performed within the limited time, the program flow returns to stepS116 to decide again whether or not the laser wavelength coincides withthe set wavelength.

[0079]FIG. 12 is a flowchart showing the probe mounting operation instep S12 of FIG. 10. According to this flowchart, mounting of the probeis performed in step S121. The probe may be mounted initially orimmediately before the setting of the probe. Thus the probe is permittedto be mounted any time before the setting of the probe. Configurationand intensity distribution of an irradiating beam of the laser light tothe focus such as cancer vary depending on the type of the probe, andtherefore an appropriate probe is to be selected according to the focusby a doctor.

[0080] Subsequently, the probe transfer characteristics areautomatically or manually set in step S122. Thus, a variety of probescan be used. Taking a transfer efficiency of the laser light of theprobe as an example, the transfer efficiency also varies depending onthe type of the probe. In the case of a probe of an identical type,there is an inevitable variation in the transfer efficiency due to avariation in manufacturing. However, the laser apparatus can onlydirectly control the oscillation conditions of the semiconductor laser,and therefore the conditions (output, wavelength, energy quantity,intensity distribution and so forth) of laser light to be practicallyapplied to the focus will vary every time the probe is changed unless acorrection according to individual probe transfer characteristic isreflected on the control of the laser. In view of the above, setting andmeasuring of the probe transfer characteristics are performed in thepresent embodiment.

[0081] The setting ofthe probe transfer characteristics is, as describedearlier, effected when the probe is mounted to the laser apparatus.Practically, the setting is automatically effected by readingcharacteristic information (transfer efficiency, intensity distributionand so forth of laser light) of the probe recorded in the connectorsection of the probe by means of the connector 54 of the laserapparatus. When a probe of which characteristic information is notrecorded is used, the characteristic values can be manually set at theinput section 52.

[0082] Then, a probe test, i.e., measurement of the transfercharacteristics of the probe is executed in step S123, and the result isdisplayed.

[0083] By subsequently executing the probe test, it is inspected whetheror not the probe transfer characteristics set as described above isactually obtained. Practically, by executing the probe test in a statein which the foremost end of the probe is inserted in the irradiatinglight characteristic measuring means 53, the oscillation control section57 controls the laser units 51 a and 51 b in specified oscillationconditions to irradiate laser light, and the characteristics (output,wavelength, intensity distribution and so forth) of the laser lightactually irradiated from the probe are measured by the irradiating lightcharacteristic measuring means 53. The oscillation conditions in thiscase are transferred from the oscillation control section 57 to theabnormality detecting means 62, and the measurement results of theirradiating laser light characteristics are transferred to theabnormality detecting means 62 via the oscillation control section 57.The abnormality detecting means 62 decides whether or not an abnormalityis occurring in the probe by calculating the probe transfercharacteristics from the above-mentioned two sorts of information andcomparing them with the probe transfer characteristics set as describedearlier. In other words, the abnormality detecting means 62 decideswhether or not an abnormality is occurring in the probe by calculatingthe probe transfer characteristics from the laser oscillation conditionsand the irradiating light characteristic measurement results andcomparing the calculation results with the probe transfercharacteristics set as described earlier.

[0084] Then, in step S124, the characteristic measurement results andthe set characteristics are compared with each other. When the measuredcharacteristics are correct (normal), the program flow proceeds to stepS125. When the characteristics are incorrect (abnormal), the programflow proceeds to step S126. In regard to the probe transfercharacteristics, assuming that, for example, the transfer efficiency,which was 80% in the manufacturing stage, is 50% as a result of themeasurement of the present probe test, the transfer efficiency of thelaser light can be considered to be reduced due to a breakage of theprobe or smear of the foremost end of the probe or the like. Therefore,an alarm indication is displayed in the displaying unit 10 via thedisplay control section 61 in step S126 to proceed step S127.

[0085] In step S127, it is decided whether or not the measurement isexecuted again. When the measurement is executed again, the program flowreturns to step S123, and the measurement is executed to compare againthe characteristic measurement results with the set characteristics instep S124. If it is required to measure the probe transfercharacteristics for the reason that an abnormality is occurring in theprobe due to breakage of the probe or smear of the foremost end of theprobe or the like, the probe test can be executed again. Otherwise, whenthe measurement is not executed again in step S127, the program flowproceeds to step S128 to decide whether or not the probe is used withthe current characteristics. When the probe is used, the program flowproceeds to step S125. Only in the case where the probe must be used ina deteriorated state for a reason such that no substitute probe isprepared regardless of the fact that the probe has an abnormality, “useof the probe with the current (deteriorated) characteristics” is to beselected. It is normally appropriate to replace the probe. The reasonwhy such a mode is availed is to prepare for the case where treatment isrequired to be performed even though the treatment efficiency isdegraded (e.g., a longer time is required due to a lowered output).

[0086] When the current probe is not used in step S128, the program flowproceeds to step 129.

[0087] In step S125, a maximum output of the probe in use is decided.This decision is made in a manner as follows. For example, if themaximum output of the laser apparatus is 500 mW, the maximum output willbe 250 mW when the transfer efficiency of the probe in use is 50%. Thus,the maximum output of the actual irradiating laser light to the affectedpart depends on the probe to be used. The maximum output intensity ofthe irradiating light is the maximum value of the output intensity ofthe irradiating light which can be set in the next item of “setting ofoutput and energy quantity”. The maximum output intensity of theirradiating light is calculated based on the transfer efficiency of theprobe calculated in the stage of the probe test by the abnormalitydetecting means 62, and the maximum output intensity of the irradiatinglight is displayed in the displaying unit 10. After the maximum outputis decided, the program flow 20 terminates.

[0088] Otherwise, when the probe is not used with the currentcharacteristics in step S128, the program flow proceeds co step S129 todecide whether or not the probe is to be replaced. When the probe is notreplaced, the program flow abnormally terminates in step S131. When theprobe is determined to be replaced in step S129, the program flowproceeds to step S130 to dismount the probe and mount a new probe.Thereafter, the program flow returns to step S122.

[0089]FIG. 13 is a flowchart showing the output and energy quantitysetting operation in step S13 of FIG. 10. According to this flowchart,the output intensity of the irradiating light is set and the irradiationenergy quantity is set in step S141. The setting of the output intensityof the irradiating light and the setting of the irradiation energyquantity can be performed independently at any time. The setting ofthese values influences calculation of an irradiating time in step S142.In regard to the “setting of the output intensity of the irradiatinglight and setting of the irradiation energy quantity”, the outputintensity of the irradiating light is set within a range below themaximum output intensity of the irradiating light set in step S125 inFIG. 12. Practical setting values of the output intensity of theirradiating light and the irradiation energy quantity are decided by thedoctor according to treatment conditions. The setting is performed atthe input section 52.

[0090] Subsequently, the irradiating time is calculated in step S142,and the result is displayed in the displaying unit 10. From theirradiation energy quantity and the output intensity of the irradiatinglight set as described above, the irradiating time is calculated by theenergy quantity control section 59, and the result is displayed in thedisplaying unit 10 via the oscillation control section 57 and thedisplay control section 61. The calculation is executed according to thefollowing relationship:

irradiation energy quantity [J]=output intensity of the irradiatinglight [W]×irradiating time [sec.]

[0091] For example, assuming that the output intensity ofthe irradiatinglight is set to 200 mW and the irradiation energy quantity is set to 200J, then the irradiating time is calculated and displayed as:

200 J÷0.2 W=1000 sec.

[0092] Subsequently, it is decided whether or not the treatmentcondition is changed in step S143. When the treatment condition ischanged, the program flow returns to step S141. When the treatmentcondition is not changed, the program flow terminates. This setting isjust for the treatment conditions, and therefore the necessity for thechange is decided strictly by the doctor. As an example of the change,in order to reduce the irradiating time of 1000 seconds (=16 minutes and40 seconds), the output intensity of the irradiating light is sometimesset to 400 mW (the irradiating time is 500 seconds) in theabove-mentioned setting. It is to be noted that the change is effectedby the doctor himself or herself when the maximum output intensity oftheirradiating light is erroneously 400 mW and the doctor decides that theirradiation at 400 mW causes no problem.

[0093]FIG. 14 is a flowchart showing the irradiation energy quantitycontrol operation in step S4 of FIG. B. According to this flowchart, itis decided whether or not the output from each laser unit is correct(normal) in step S151. When the output is correct in step S151, theprogram flow proceeds to step S152 to integrate the irradiation energyquantity based on the total output of the irradiating light by theenergy quantity control section 59 and then display it in the displayingunit 10. Thereafter, the residual irradiation time is calculated by thetime measuring section 58 and is then displayed in the displaying unit10 in step S153 to terminate the program flow.

[0094] Otherwise, when the output is not correct in step S151, theprogram flow proceeds to step S154 to decrease the set output value ofthe abnormal laser unit. Then, the condition of the abnormal laser unitis displayed in the displaying unit 10 in step S155, the set outputvalue of the other laser unit is increased in step S156, a decision ofwhether or not the total output intensity ofthe irradiating light iscoincident with the set value in step S157 is made. When the totaloutput intensity coincident with the set value in step S157, the programflow proceeds to step S152. When the total output intensity is notcoincided with the set value in step S157, the set value of the totaloutput intensity of the irradiating light is decreased in step S158 andthen the decrease of the total output intensity is displayed as an alarmindication in the displaying unit 10 in step S159 to proceed to stepS152.

[0095] Operation of the diagnostic/treatment apparatus having theabove-mentioned construction will be discussed with reference to theflowchart shown in FIG. 8. In step S1 of FIG. 8, first an operator suchas a doctor sets the wavelength (step S11 of FIG. 10), energy quantityand irradiation intensity distribution of an irradiating light 85 forobtaining an optimum effect for treatment or diagnosis by taking intoconsideration the type and the excitation efficiency characteristic ofthe photosensitizer to be used, irradiating light permeability dependingon the size, depth, and tissue components of the focus and so forth.Then the values from the input section 52 are inputted to the controlunit 7 (steps S11 and S13 of FIG. 10, steps S111 through S115 of FIG.11, and step S141 of FIG. 13). When a wavelength that is shifted fromthe optimum wavelength of the photosensitizer is used in a manner asdescribed above and hereinafter or in a similar case, the type and thewavelength characteristic of the excitation efficiency of thephotosensitizer are additionally inputted. Further, transfercharacteristics of the transfer efficiency, irradiating light intensitydistribution and so forth of a laser probe 80 to be used are inputted(step S12 of FIG. 10).

[0096] Thus the inputted setting values and the transfer characteristicsof the laser probe 80 are stored in the setting condition storagesection 55 (step S122 in FIG. 12). Among the setting values, the outputintensity and the irradiating time for determining the irradiationenergy quantity are corrected as needed in a manner as describedhereinafter by the wavelength correcting section 56 to decideirradiation conditions. Then, the control unit 7 oscillates beams oflaser light 72 a and 72 b for a short time by using the oscillationcontrol section 57 with shutters 11 a and 11 b closed (step S2 in FIG.8), and then it is confirmed whether or not a specified wavelength andoutput intensity are obtained according to the detection results of thedetecting units 9 of the semiconductor laser units 51 a and 51 b (stepsS116 and S117 of FIG. 11). In this stage, when the required outputintensity is not obtained, an irradiation energy quantity control, forcompensating a fluctuation of the output, is effected by varying theirradiating time in a manner as described hereinafter in the stage ofirradiation. Otherwise, when the set wavelength is not obtained, thefact is displayed for alarming the operator to set again the irradiationconditions within a range of usable wavelengths. In this stage, when afluctuation of wavelength exceeding a permitted range or reduction ofoutput intensity is detected, it is decided that an abnormality of laseris occurring, and a stopping of the oscillation and a display of anabnormality for the alarm are performed (step S118 of FIG. 11).

[0097] Subsequently, when the probe test is selected at the inputsection 52 with the connector 54 of the laser probe 80 connected to theemission outlet 75 and with the foremost end portion 83 connected to theirradiation outlet of the irradiating light characteristic measuringmeans S3 (step S123 in FIG. 12), after confirming that the foremost endportion 83 is connected to the irradiating light characteristicmeasuring means 53, the control unit 7 emits laser light by opening theshutters 11 a and 11 b. In this stage, the measuring section of theirradiating light characteristic measuring means 53 measures thewavelength, total output intensity, and intensity distribution of theirradiating light 85 irradiated actually from the foremost end portion83, and transmits the result to the control unit 7. The oscillationcontrol section S7 of the control unit 7 calculates the transfercharacteristics of the laser probe 80 from the measurement results ofthe irradiating light characteristic measuring means S3 and the outputcharacteristic detection results of the detecting units 9 of thesemiconductor laser units 51 a and 51 b.

[0098] Subsequently, during irradiation, the output ofthe emitted laserlight is converted into an output of the irradiating light 85 by usingthe calculated values in the above-mentioned stage as transfercharacteristic values of the laser probe 80, and the obtained value istransferred to the energy quantity control section 59 (step S125 of FIG.12). The calculated transfer characteristics are further transmitted tothe abnormality detecting means 62 together with the transfercharacteristics of the laser probe 80 set initially to decide whether ornot an abnormality such as deterioration is occurring in the laser probe80 (step S124 of FIG. 12). When the abnormality detecting means 62decides that an abnormality is occurring, the contents of theabnormality are transferred to the display control section 61 and aredisplayed in the displaying unit 10 so as to alarm the operator toreplace the probe (step S129 of FIG. 12). Such a probe test is effectedas needed for output intensities and wavelengths in several steps.Further, the diagnostic/treatment apparatus ofthe present embodiment hasinhibiting means for inhibiting the irradiation unless the probe test isonce effected after the power is turned on.

[0099] Thus, the output characteristics of the semiconductor laser units51 a and 51 b are controlled, so that the wavelength, total outputintensity, and intensity distribution of the irradiating light 85 arecontrolled via the transfer characteristics of the laser probe 80 used.

[0100] The preparation for the irradiation of the diagnostic/treatmentapparatus is thus completed through the aforementioned operations,thereby allowing the irradiating light 85 to start being irradiated tothe part to be treated. A control operation during irradiation will bediscussed below.

[0101] During irradiation ofthe irradiating light 85 (steps S2 and S3 ofFIG. 8), the oscillation control section 57 controls the outputcharacteristics of the semiconductor laser units 51 a and 51 b in amanner as described earlier, so that the wavelength, total outputintensity, and the intensity distribution ofthe irradiating light 85 arecontrolled via the actual transfer characteristics ofthe laser probe 80used. Simultaneously with this control, the energy quantity controlsection 59 sequentially integrates the output intensity of theirradiating light 85, obtained through conversion as transmitted fromthe oscillation control section 57, as an energy quantity of irradiationwhich has been irradiated according to a time-measured signal of thetime measuring section 58 (steps S4 and S7 of FIG. 8). Further, theintegrated irradiation energy quantity is compared with the set value ofthe irradiation energy quantity to be irradiated set initially tocalculate the remaining irradiation energy quantity and irradiating timeto be required (step S142 of FIG. 13). During the above-mentioned time,the set values and the current values of the wavelength and the outputintensity of the sequentially irradiated light are transmitted, whilethe set values, the already irradiated portions, and the remainingportions ofthe irradiating time and the irradiation energy quantity aretransmitted each from the display control section 61 to the displayingunit 10 to be displayed. When an irradiation energy quantity equal tothe set value is irradiated, the emission control section 60 closes theshutters 11 a and 11 b to complete the irradiation of the irradiatinglight 85, the fact that the operation has been normally terminated isdisplayed in the displaying unit 10, and the apparatus is put in astandby state (steps S5 and S8 of FIG. 8). It is to be noted that theoperator can of course execute a stopping of the irradiating operationeven in the irradiation stage.

[0102] Next, the following will describe an operation of controlling theirradiation energy quantity of the irradiating light 85 when afluctuation is occurring in the output of the laser light duringirradiation. For example, when the output intensity of the laser unit 51a reduces, the oscillation control section 57 tries to increases theinput of the laser unit 51 a to maintain the output intensity of theunit 51 a. However, if the specified output intensity cannot be obtained(step S143 of FIG. 13), the oscillation control section 57 obtains themaximum output intensity that the laser unit 51 a can stably obtain at aspecified wavelength, and decides the maximum output intensity as theoutput intensity of the laser unit 51 a. In this case, there is effecteda compensation for a quantity corresponding to the reduction of theoutput intensity at the laser unit 51 a by increasing the outputintensity of the laser unit 51 b to continue the irradiation. When thereduction of the output intensity at the laser unit 51 a is sosignificant that no compensation therefor is effected by the laser unit51 b resulting in a shortage of the output intensity, the outputintensity of the irradiating light is reduced. However, by increasingthe irradiating time, the initially set irradiation energy quantity isobtained. In this case, an alarm indicating the reduction of the outputintensity is also displayed in the displaying unit 10 in addition to theaforementioned set value and the current value of the output intensity.

[0103] When the reduction of the output intensity is too significant orthe output is unstable, the oscillation control section 57 stops theoscillation ofthe laser as the result of an abnormal failure. However,when the operator does not desire continuation of the irradiation at thereduced output intensity even if the reduction of the output intensityis within a permitted range, the irradiation can be of course stopped bythe operator as described earlier.

[0104] Next, the following will describe an operation of controlling theirradiation energy quantity of the irradiating light 85 when a laserlight having a wavelength shifted from the optimum wavelength of thephotosensitizer is used. Excitation is caused in the photosensitizer bythe energy of the irradiating light 85, and an excitation efficiencydepends on the wavelength of the irradiating light 85. As an example, arelationship between the excitation efficiency ξ and the wavelength λ inthe case where a chlorin series NPe6 (trade name) is used as thephotosensitizer is shown in FIG. 7 and, expressed by Equation 1:

[0105] ξ=f(λ)

[0106] where the excitation efficiency ξ is normalized on the assumptionthat the excitation efficiency ξ=1 with respect to the irradiating light85 having a wavelength λ₀=664 nm optimum for PDT.

[0107] According to FIG. 7, for example, the excitation efficiency withrespect to the irradiated light 85 having the wavelength λ=652 nm has avalue of only 0.5. Even though the excitation efficiency is reduced asdiscussed above, there is sometimes the case where an irradiating light85 having a wavelength of 652 nm, which is shifted from the optimumwavelength of 664 nm, is used in order to obtain more clearly obtain animage of fluorescence for diagnosing the part to be treated as describedabove. Furthermore, when the temperature control of the semiconductorlaser units 51 a and 51 b is in a bad condition, it is inevitable to usethe irradiating light 85 having a wavelength shifted from the optimumwavelength of 664 nm. In such a case, in order to obtain the sametreatment effect as that achieved by PDT executed with an irradiationenergy of 300 J at the wavelength of 664 nm of the irradiating light 85,an irradiation energy of 600 J is required when the wavelength oftheirradiating light 85 is 652 nm. Therefore, the output intensity of theirradiating light 85 is normally doubled. However, according to thepresent embodiment, by paying attention to the irradiation energyquantity as described above, a control is achieved through correction sothat the irradiation energy quantity, which is the time integral valueof the output. intensity, is doubled by increasing the irradiating timeeven if the output intensity of the irradiating light 85 cannot bedoubled. Thus, when the irradiating light 85 having a wavelength λshifted from the optimum absorption wavelength is used, the wavelengthcorrecting section 56 corrects a control target value of the irradiationenergy quantity based on the excitation efficiency ξ of thephotosensitizer given by Equation 1 and decides the irradiationconditions.

[0108] Further, when a fluctuation of wavelength occurs in theirradiating light 85 during irradiation, the control target value of theirradiation energy quantity is corrected by the wavelength in the samemanner as described above. The correction is applied to the remainingirradiation energy quantity calculated by the aforementioned energyquantity control section 59 at the point of time when the fluctuation ofthe wavelength occurs.

[0109] Next, a backup operation of the laser will be discussed. Thediagnostic/treatment apparatus of the embodiment is provided with twosemiconductor laser units 51 a and 51 b each being capable of obtaininga sufficient output as a light source. The total oscillationcharacteristic is controlled by individually controlling thesemiconductor laser units 51 a and 51 b by the oscillation controlsection 57 of the control unit 7. With the above-mentioned operation,when, for example, the output intensity of the laser unit 51 a isreduced, the total output intensity is maintained at a specified valueby increasing the output intensity of the other laser unit 51 b.Further, when the laser unit 51 a causes a failure and thus stopscompletely and the specified output intensity cannot be obtained singlyby the laser unit 51 b, the specified irradiation energy is obtained byincreasing the irradiating time.

[0110] According to the embodiment as described above, in order toobtain the intended treatment effect of PDT, the control unit 7comprised of the two semiconductor laser units 51 a and 51 b,irradiating light characteristic measuring means 53, setting conditionstorage section 55, wavelength correcting section 56, oscillationcontrol section 57, time measuring section 58, energy quantity controlsection 59, emission control section 60, display control section 61, andabnormality detecting means 62 is provided paying attention to theirradiation energy quantity of the irradiating light 85. With theabove-mentioned arrangement, the actual transfer characteristics ofthelaser probe in use can be confirmed, by which the outputs of the emittedbeams of laser light 72 a and 72 b can be converted into the output ofthe irradiating light 85, and the abnormality of the laser probe can bedetected. Furthermore, even when the output intensity of onesemiconductor laser unit 51 a is reduced, compensation for the reductioncan be effected by increasing the output intensity of the othersemiconductor laser unit 51 b. Furthermore, the irradiation energyquantity of the irradiating light 85 can be integrated and controlled,and therefore the irradiation energy quantity of the irradiating light85 can be controlled so that it is maintained at the specified value byincreasing the irradiating time when the total output intensity of theemitted laser light is reduced. Furthermore, when the irradiating light85 having a wavelength shifted from the optimum wavelength of thephotosensitizer is irradiated, an irradiation energy quantity capable ofobtaining the intended treatment and/or diagnosis effect can beobtained.

[0111] The embodiment is provided with two semiconductor laser units.However, when a greater output intensity is required, or when a highreliability is required, three or more plural semiconductor laser unitsmay be of course provided. When the plurality of semiconductor laserunits are provided, they are still less bulky, less heavy, and lessexpensive than the excimer dye laser.

[0112] Furthermore, the transfer characteristics such as the transferefficiency and irradiating light intensity distribution of the laserprobe 80 to be used are inputted by the operator. However, it ispossible to read the initial transfer characteristics of the laser probe80 recorded at the connector 54 by the emission outlet 75 and thentransfer them to the setting condition storage section 55 when theconnector 54 of the laser probe 80 is connected to the emission outlet75.

[0113] Furthermore, in regard to the correction of the control targetvalue of the irradiation energy quantity depending on the fluctuationofthe wavelength ofthe irradiating light 85, the control is executedbased on the excitation efficiency characteristics with respect to thewavelength of the photosensitizer. However, it is acceptable topreliminarily calculate correction factor characteristics of therequired irradiation energy quantity with respect to the wavelengthaccording to Equation 1 and to correct the control target value of theirradiation energy quantity based on the correction factorcharacteristics.

[0114] As described above, the present invention includes theirradiation energy quantity control means for the irradiating light, andby providing control means for executing control so that the irradiationenergy quantity becomes a specified quantity, there can be implemented adiagnostic/treatment apparatus capable of controlling, to a specifiedvalue, the energy quantity ofthe irradiating light that is irradiatedfrom the foremost end portion of the laser probe and thus directlyinfluencing the treatment effect.

[0115] Furthermore, by providing the wavelength correction means forcorrecting the control target value ofthe irradiation energy quantity bythe wavelength of the irradiating light, there can be implemented adiagnostic/treatment apparatus capable of obtaining an irradiationenergy quantity which can achieve the same treatment effect as thatachieved at the optimum absorption wavelength even when the wavelengthof the irradiating light is shifted from the optimum absorptionwavelength of the photosensitizer to be used.

[0116] Furthermore, by providing a plurality of laser units as a lightsource and oscillation control means for controlling the totaloscillation characteristics by controlling the plurality of laser units,and individually controlling the plurality of laser units, there can beimplemented a diagnostic/treatment apparatus obtaining a specifiedirradiation energy capable of obtaining a specified irradiation energyquantity even when an abnormality occurs partially in the light source.

[0117] Therefore, according to the present invention, the optimumcontrol is multilaterally achieved to irradiate an irradiating lightconstantly having an appropriate energy, so that a superior diagnostic/treatment apparatus capable of executing exact diagnosis and effectivetreatment can be provided.

[0118] Although the present invention has been fully described inconnection with the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

What is claimed is:
 1. A method comprising: using a semiconductor laseras a light source, wherein a wavelength of said semiconductor laser canbe controlled; and diagnosing or treating a focus of cancer or the likeby causing excitation of a photosensitizer by irradiating light from alight source to the focus at which the photosensitizer having anaffinity to a tumor is preliminarily accumulated.
 2. The methodaccording to claim 1, further comprising: detecting an oscillationwavelength of said semiconductor laser; and controlling a temperature ofsaid semiconductor laser based on a result of said detecting.
 3. Themethod according to claim 1, further comprising controlling atemperature of said semiconductor laser based on a relationship betweenthe temperature and an oscillation wavelength of said semiconductorlaser.
 4. A method comprising: diagnosing or treating a focus of canceror the like by causing excitation of a photosensitizer by irradiatinglight from a light source to the focus at which the photosensitizerhaving an affinity to a tumor is preliminarily accumulated; and using asemiconductor laser as a light source, wherein excitation light of saidsemiconductor laser has a narrow half width and a center wavelength ofthe excitation light can be controlled.
 5. The method according to claim4, further comprising executing wavelength control by controlling atemperature of said semiconductor laser.
 6. The method according toclaim 5, further comprising: detecting an oscillation wavelength of saidsemiconductor laser; and controlling the temperature of saidsemiconductor laser based on a result of said detecting.
 7. The methodaccording to claim 5, further comprising controlling the temperature ofsaid semiconductor laser based on a relationship between the temperatureand an oscillation wavelength of said semiconductor laser.
 8. The methodaccording to claim 5, further comprising: inputting a target wavelengthfor wavelength control; and displaying a result of the input.
 9. Themethod according to claim 5, further comprising: inputting a targetwavelength for wavelength control; and interrupting the laser light whenthe wavelength of the laser light does not conform to a condition of theinput wavelength.
 10. The method according to claim 4, furthercomprising: using a medical laser apparatus in which the centerwavelength of laser light is within a range of 664±5 nm; and using achlorin series substance as the photosensitizer.
 11. The methodaccording to claim 4, further comprising: using a medical laserapparatus in which the center wavelength of laser light is within arange of 650±10 nm; and using a pheophorbide series substance as thephotosensitizer.
 12. A method comprising: diagnosing or treating a focusof cancer or the like by causing excitation of a photosensitizer byirradiating light from a light source to the focus at which thephotosensitizer having an affinity to a tumor is preliminarilyaccumulated; using a semiconductor laser as a light source, whereinexcitation light of said semiconductor laser has a narrow half width anda center wavelength of the excitation light can be controlled; andanalyzing an image of fluorescence obtained by separating onlyfluorescence light emitted from the photosensitizer by the excitationlight.
 13. The method according to claim 12, further comprisingdisplaying a result of the analysis of the fluorescence light image. 14.The method according to claim 12, further comprising using a band-passfilter which allows only light having a wavelength ofthe fluorescencelight and around the wavelength in separating the fluorescence light.15. The method according to claim 13, further comprising putting thecenter wavelength of the excitation light farther apart from thewavelength of the fluorescence light during diagnosis than duringtreatment.
 16. The method according to claim 14, further comprising:using, when diagnosing and treating cancer, a chlorin seriesphotosensitizer as the photosensitizer at which the center wavelengthofthe excitation light is within a range of 664±5 nm; and using, as afilter for observation, a band-pass filter which allows light having awavelength of 670 nm and thereabout to pass therethrough and interruptsa wavelength of a light source which serves as the excitation light. 17.The method according to claim 14, further comprising: using, whendiagnosing and treating cancer, a pheophorbide series photosensitizer asthe photosensitizer at which the center wavelength ofthe excitationlight is within a range of 650±5 nm; and using, as a filter forobservation, a band-pass filter which allows light having a wavelengthof 654 nm and thereabout to pass therethrough and interrupts awavelength of a light source which serves as the excitation point.
 18. Amedical laser apparatus comprising a wavelength correcting unit forcorrecting a control target value of an irradiation energy quantity by awavelength of irradiating light.
 19. The medical laser apparatusaccording to claim 18, wherein said wavelength correcting unit isoperable to correct the control target value of the irradiation energyquantity ofthe irradiating light based on an optical excitationefficiency characteristic relative to a wavelength of a photosensitizer.20. The method according to claim 4, wherein the control is effected sothat the irradiation energy quantity coincides with a specifiedquantity.
 21. The method according to claim 20, wherein the control iseffected so that the irradiation energy quantity coincides with aspecified quantity by controlling at least either one of an outputintensity and an irradiating time of the irradiating light.
 22. Themethod according to claim 20, further comprising measuring irradiationcharacteristics ofthe irradiating light irradiated from an optical pathfor transmitting the irradiating light to the focus.
 23. The methodaccording to claim 22, further comprising detecting and displaying anabnormality for alarm from a result of measurement of the irradiatingcharacteristics.
 24. The method according claim 20, further comprising:using a plurality of laser units as a light source of the irradiatinglight; and controlling a total oscillation characteristic byindividually controlling the plurality of laser units.
 25. The methodaccording to claim 4, further comprising correcting a target value of anirradiation energy irradiation quantity based on the wavelength of theirradiation light.
 26. The method according to claim 25, wherein in saidcorrecting, the control target value of the irradiation energy quantityofthe irradiating light is excitation efficiency a wavelength ofthecorrected based on optical excitation efficiency characteristicsrelative to a wavelength of the photosensitizer.
 27. The methodaccording to claim 20, wherein in the control, correction of a targetvalue of the irradiation energy quantity is executed based on thewavelength of the irradiating light.